37个含硫芳香族化合物理化参数的相关性分析

本文对37个含硫(S,SO,SO_2)芳香族化合物的理化参数作了统计分析,在水解速率常数k与取代基常数之间建立了几个多元回归方程,并根据各化合物的因子得分和实验设计方法为生物试验挑选出了8个有代表性的化合物。     

Defensive secretion of a flightless grasshopper: Failure to prevent lizard attack

Summary We tested the role of a grasshopper defensive secretion in deterring lizard predation. Adults, but not young larvae, of the chemically defended lubber grasshopperRomalea guttata (=microptera) froth a volatile secretion when attacked by predators. The lizardAnolis carolinensis failed to strike juvenile lubbers (which lack secretion) in laboratory trials. Survivorship of palatable crickets loaded with secretion offered toA. carolinensis was not significantly different from survivorship of control crickets. In experiments designed to investigate if lizards learn an aversion to the secretion, striking times forSceloporus undulatus fed wax worms coated with secretion were not significantly different over three days of trials. Three primary conclusions are drawn from these data. First, the secretion may not be necessary for lubber protection from lizards. Second, lubber secretion does not appear to deter lizards from attacking or eating prey items. Third, lizards do not appear to develop an aversion to the secretion.     

几种萃取剂对土壤中重金属生物有效部分的萃取效果

采用6种萃取剂:pH=7的0.01mol/L CaCl_2、pH=7.3的0.005mol/L DTPA+0.1mol/L TEA(三乙醇胺)+0.01mol/L CaCl_2O.1mol/L NaNO_3、0.43mol/L HOAc、pH=7的0.05mol/L EDTA和pH=4.65的0.5mol/L NH_4OAc+0.02mol/L EDTA浸取液.对污染土壤中的重金属Cu、Zn、Cd、Pb、的进行了萃取,并比较了萃取剂的萃取能力。实验结果表明,HOAc、EDTA以及NH_4OAc-EDTA萃取各种重金属的能力远远大于其它几种萃取剂的萃取能力,是比较理想的萃取剂。     

一种新的快速测定水中COD的消化一分光光度法

探讨了在MnSO_4-CuSO_4复合催化剂、硫-磷混酸体系中,对样品进行恒温密封消解,用分光光度法测定溶液的COD值。实验得出测定化学需氧量的最佳条件:混酸H_2SO_4-H_3PO_4体积比为4:1,催化剂MnSO_4-CuSO_4质量比为1:2,MnSO_4-CuSO_4的总量为0．03g,消解温度为165℃,消解时间为15min。实验结果表明,此方法的测定结果与重铬酸钾法测定结果的相对误差≤5%,且有较好的重现性及较高的准确度与精密度。本法可同时消解多个试样,适用于大批量试样COD的测定,使试样的消解时间由标准法的2h缩短到了15min,同时用MnSO_4-CuSO_4复合催化剂代替价格昂贵的A_(g2)SO_4,大大降低了分析成本。     

Hydroquinones from defensive secretion of a giant Pacific millipede, <Emphasis Type="Italic">Acladocricus setigerus</Emphasis> (Diplopoda: Spirobolida)

Summary. The presence of considerable quantities of hydroquinones including hydroquinone, 2-methylhydroquinone, 2,3- dimethoxyhydroquinone, 2-methoxy-3-methylhydroquinone, and 2,3-dimethoxy-5-methylhydroquinone renders the defensive secretion of Acladocricus setigerus (Silvestri, 1897) significantly different from that of other quinone-producing millipedes. In addition, two hitherto undescribed compounds, namely, 2,3-dimethoxy-5-methylhydroquinone and 2-methyl-3,4-methylenedioxyphenol, were characterized from the defensive secretion. However, it is uncertain if the latter compound is formed after the release of the secretion. The two major compounds, 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone, constitute about 75% of the defensive fluid. Furthermore, hydrocarbons, which are typically present in the secretions of most other arthropods that use benzoquinones as repellents, are notably absent in the secretion of A. setigerus.     

Leaf variation in iridoid glycoside content ofPlantago lanceolata (Plantaginaceae) and oviposition of the buckeye,Junonia coenia (Nymphalidae)

Summary Chemical analysis of each individual leaf of fivePlantago lanceolata (Plantaginaceae) plants showed that iridoid glycoside content increased from undetectable in the oldest photosynthetic leaves to over 9% dry weight in the youngest leaves. The relative proportion of the two iridoid glycosides inP. lanceolata also changed with leaf age: older leaves had significantly more aucubin, whereas the youngest leaves had primarily or solely catalpol. Oviposition tests with femaleJunonia coenia (Nymphalidae) butterflies, showed that they laid most of their eggs on new leaves.     

天然水体中有机酸当量浓度的确定方法

本文根据天然水体中溶解有机在碳与化学需氧量和生化需氧量之间的相关性，以及有机酸当量和水体溶解有机碳之间的近似定量关系，提出了由化学需氧量或生化需氧量得到溶解有机碳或总有机碳浓度，最终得到有机酸和有机酸根当量浓度的转换方法，为大区域天然水体有机酸碱缓冲作用的评估提供了一个实用的转换途径。     

Acidification of groundwater in water-filled gravel pits -- a new environmental and geomedical threat

Swimmers and users of motor boats frequenting old, water-filled gravel pits in Kiiminki, Northern Finland, found in August 1993 that they were suffering from painful irritation of the eyes and that their boats had developed a finely polished surface on their aluminium hulls, evidently due to the corrosive action of the water. Subsequent measurements carried out by the water authority showed that the pH of the water in some of the pits was extremely low, reaching a value of 3.4 at its lowest. To find out the causes of the abnormally low pH values, the present authors began systematic measurements of the pH and determination of the chemical composition (Si, Al, Ca, Mg, K, Na, Fe, Mn, Cu, Pb, Ni, Cd, Cl^-, NO₃ ^-, SO₄ ^2-) of the water in 23 gravel pits. In addition, a series of laboratory experiments was carried out to examine the interaction of water with samples of the soil and bedrock of the area to evaluate the role of this process as a possible cause of the acidification. The results show that the reaction of water with the moderately to intensively weathered sulphide and jarosite-bearing black schists, typical of the bedrock of the area, can bring about aqueous solutions similar in pH and sulphate--nitrate ratios to those found naturally in the gravel pits. The contribution of other possible mechanisms, e.g. acidic precipitation as such or combined with enhanced evaporation, the possible use of the pits as dumping sites for acidic waste or the flow or seepage of acidic peat-bog waters into the pits from the surrounding wetlands, cannot be ruled out entirely, but their contribution seems to be of minor importance. Since the concentrations of several heavy metals (notably Pb, Cd, Ni, Fe and Mn) and of sulphate and aluminium has increased in the pit water as a result of the acidification process and exceed the norms laid down in the EU Drinking Water Directive, acidification of water in gravel pits due to the oxidation of sulphides must be regarded as a new, serious environmental and geomedical threat which has so far remained poorly known or unrecognised.     

Sequestration of pyrrolizidine alkaloids by larvae ofTellervo zoilus (Lepidoptera: Ithomiinae) and their role in the chemical protection of adults against the spiderNephila maculata (Araneidae)

Summary Life stages of the primitive Australian ithomiine butterflyTellervo zoilus and its larval hostplant, the apocynaceous vineParsonsia straminea, were quantitatively assayed for pyrrolizidine alkaloids (PAs). PAs were found in all stages, mainly as N-oxides, being most concentrated in larvae and freshly-emerged adults. Although adults feed at various confirmed PA sources this probably does not compensate for losses, as wild-caught adults had considerably lower concentrations of PAs. The main alkaloid present in both freshly-emerged adults and in leaves of the host-plant was lycopsamine (1b), stored by butterflies in the N-oxide form. Its presence in higher proportion, in relation to intermedine (1a), in larvae, pupae and adults ofTellervo in relation to the host-plants suggests the inversion of intermedine to lycopsamine by the insects. No 14-member ring macrocyclic PAs were detected in either food-plant or butterflies. Several other PAs were found in wild-caught adults reflecting visits to other PA sources. PAs were also found in high concentrations in freshly-emerged individuals of the danaineEuploea core bred onParsonsia straminea. Wild-caughtDanaus affinis had high PA levels acquired from adult feeding. Freshly emergedEuploea raised onIschnocarpus frutescens andDanaus raised onIschnostemma carnosum (both PA-free) were preyed on by the orb weaving spiderNephila maculata, and showed no PAs. In all cases where PAs were present, most butterflies were liberated, usually cut out of the web unharmed, byNephila. The spider's response was not closely linked to PA concentration, however, and may also depend on hunger levels and previous experience with PA-containing butterflies. All control and other non-PA containing butterflies were consumed although rejection of some body parts of freshly-emergedDanaus affinis suggests that compounds other than PAs may be involved.     

二种高硫煤中硫氮化学形态的研究

利用ＸＰＳ技术研究了贵定煤和西班牙Ｍｅｑｕｉｅｎｚａ煤中硫和氮化学形态的分布，并结合硫Ｋ－边ＸＡＮＥＳ和Ｍｏｓｓｂａｕｅｒ谱着重考察贵定煤中硫化学形态。结果表明，贵定煤中含硫化合物主要以噻吩形态存在，其次为有机硫化物；而Ｍｅｑｕｉｅｎｚａ煤中以有机硫化物含量最大，噻吩硫次之，有关含氮化合物，Ｍｅｑｕｉｅｎｚａ煤以吡咯和吡啶氮为主，但在贵定煤中观察到较大浓度的氧化氮化合物。